Trailer oscillation can create vehicle stability problems. It occurs under specific conditions when a vehicle that is pulling a trailer, wherein the tow point of the trailer is rearward of all vehicle axles, for example when a light vehicle tows a trailer by way of a hitch or tow package. Trailer oscillation is a condition in which the pivot between the trailer and the towing vehicle swings in an oscillatory pattern side-to-side and/or up-and-down. The situation presents vehicle handling difficulties, particularly during heavy braking and traveling down hill. Trailer oscillation can lift the rear end of a vehicle and push the vehicle side-to-side, significantly increasing the risk of a rollover accident.
Some vehicles are equipped with inertial measurement units (IMU) including yaw sensors for stability control. These sensors can provide information regarding vehicle and trailer oscillation, but do not provide a complete solution. Preferably, such systems should include an IMU on the trailer as well, because a trailer can oscillate with the vehicle oscillating. Such solutions, however, would be expensive, and not all vehicles have IMU sensors.
Other oscillation detection schemes employ simple rules-based logic. Such systems lack robustness because of the numerous unknown vehicle and trailer dynamic possibilities. Using many different types of sensors to improve system robustness consequently makes integration of such inputs and computation of outputs very difficult. Thus, there exists a need for an improved control scheme to mitigate trailer oscillation, and which can readily adapt to numerous vehicle and trailer combinations. The system should also be able to accommodate vehicles and trailers without IMU sensor sets.